HELP! Kohler command 20 problem!

As I previously posted, I am having trouble with my Kohler command 20 on a Walker with 48" GHS. It is running rough, missing, and slight consistent backfire while running.

I have drained and cleaned gas tank, lines, and carb. Installed new gas filter, air filter and plugs. Still running rough, and seems to be overheating very quickly, even after only a couple of minutes of running at idle. The high heat seems to be coming from only the front cylinder, to the point it heats the muffler to cherry red where that cylinder exhausts into the muffler....and only after a couple of minutes of running. Could this be a stuck or burnt valve? How can I test for that? I can borrow a compression guage, but not sure how to run the test properly. I know there are some great mechanics on this site......any suggestions??? Thanks!!

definately sounds like aburned valve . Or else atight one. Disconnect the spark plug wires. set throttle in wde open position and crank it over a couple of seconds. (after removing the plug and while holding the compression tester in the spark hole-very firmly) . the compression should be 100-120 range.

Finally got around to checking the compression......both cylinders are right at 170. I guess this means it's not a burnt valve? I am thinking now that it might be the coils.....but not sure how I can test them. Any suggestions would be appreciated.

stuck valve is possible, or weak/broken valve spring. squirt a little marvel mystery oil in the cylinders and start it, or squirt some in the carb throat as it's running..(do this outside, it's gonna smoke)

does it run rough as soon as you start it, or does it happen after it heats up?

Thanks for the reply. To answer your questions, it starts easily both cold and hot, runs rough from the start but gets worse as it warms up, cooling fins are clean now but were not when this problem started, I've pulled both valve covers and valves seem to be operating properly while running, have cleaned carb out, and hadn't hit anything that would have sheared flywheel key. Also if head gasket was blown wouldn't compression have leaked down after I stopped cranking and let it sit? Any further suggesions would be greatly appreciated!!

Hmmmmm......... Thanks again for the reply...... I'm not a mechanic by any stretch of the imagination, but I have found I can fix about anything if I have the right instructions (either verbal or written manual). I guess I need to go ahead and pull the head. Hope it's as simple as a blown gasket! Any other helpful hints are always appreciated.

When a Command blows a head gasket 99% of the time it blows it into the pushrod galley.I believe you have a blown intake gasket,This is just my educated guess.You do not have a blown head gasket if you have 170PSi on both cylinders,IMO.With it running spray some carb cleaner or starting fluid around the intake of the front cylinder,if it picks up ,and smooths out,youve found the problem. BTW with an intake gasket blown the front cyl will run really lean,and that will explain the red exhaust ,and high cyl temp,and lean missfiring/backfiring. John D